DERs are small-scale electricity generation or storage sources that are located near where the electricity is needed. DERs include small residential, community, and commercial sources attached to the distribution grid. Distributed generators can be both renewable and nonrenewable. Distributed renewables are described in Cleary and Palmer (). Usually, less than 10 MW in capacity, DERs have rapidly expanded in the past 10&#;15 years; some estimates anticipate that capacity will double between and (Wood Mackenzie ). DERs are broadly categorized into fuel-based generation, zero-emissions generation, battery energy storage systems, demand response, and demand management through virtual power plants (VPPs). We discuss each of these and their specific benefits and limitations next.
Please visit our website for more information on this topic.
Fuel-based DERs include backup power generators, microturbines, biomass combustion, and combined heat and power systems. Typically, these provide essential backup power in cases of emergencies, outages, voltage issues from the grid, and severe weather events. Biomass combustion is a renewable DER; organic materials, such as agricultural and plant residues, wood, and animal waste, are converted to electricity using different methods, including direct burning or combustion (EIA ). All fuel-based DERs can be deployed at a commercial or industrial scale to meet demand at the customer site, especially during peak-load operations, and supply electricity to the distribution network.
Combustion-based DERs release heat while generating electricity. This thermal energy can be used for heating/cooling water or interior spaces and in industrial processes instead of burning more fuel. A process where both electric and thermal energy are used is called &#;combined heat and power&#; (CHP) or &#;cogeneration.&#; CHP can lower costs and environmental impacts of using fuel exclusively for heating and other purposes. Although fuel-based DERs provide reliability and low-cost options for DG, the clean electricity transition and decarbonization goals require eventually phasing out fossil DERs; these should be thought of as not a substitute for transmission but rather a source of potential demand increase as fossil fuels phase out. Users of fuel-based distributed generation will either turn to the grid (increasing strain on transmission networks) or transition to emissions-free distributed generation technologies.
DERs that generate zero CO2 emissions include small-scale solar, wind, hydropower, and hydrogen fuel cells. The most common source is solar photovoltaic (PV) panels or solar arrays (connected panels) containing cells that convert sunlight directly into power. Small-scale solar installations are defined by EIA as those that produce less than 1 MW (Lee and Moses ). These PV systems are generally found on residential and commercial rooftops and typically average 5 kW One residential rooftop panel produces 250&#;400 Watts (Allen and Tynan ). and 200 kW, respectively (Mayes ). For community solar, off-site arrays serve multiple customers, such as homes and businesses. Solar panels are one of the fastest-growing renewable energy technologies due to declining costs and policy incentives. Feed-in tariffs (utilities purchasing solar power from homeowners and businesses at fixed rates) and net-metering (customers getting credits on the bill for surplus electricity sent to the grid) both support the growth of distributed solar (Cummins Inc. ). However, because of economies of scale, the levelized cost of energy (LCOE) LCOE is the net present value of the total cost of electricity generation of a power plant over an assumed lifetime. from utility-scale solar is 25&#;40 percent that of distributed solar, and NREL predicts that it will continue to be so in the future. Even by , under the advanced technology scenario, the LCOE of residential PV is projected to be at least three times more than utility-scale PV, and commercial PV&#;s LCOE will be about 2.2 times higher. It is not clear how much of this cost gap is offset by the additional need for transmission and distribution lines or the potential environmental costs of centralized utility-scale generation. A study by the Brattle Group that takes such transmission and distribution costs into consideration concludes that utility-scale solar would still be cheaper (Tsuchida et al. ), but the analysis is limited to one utility and region of the country, and thus more research is needed.
Wind energy has the largest share of clean and renewable electricity in the United States, and grid-scale wind energy has grown at by about 30 percent per year over the last decade (EERE n.d.a). Distributed wind (DW) is defined by a plant&#;s proximity to end-use or distribution infrastructure and not its size. However, typically, DW energy uses smaller wind turbines that range from 5 kW to multi-MW and can be installed at the residential, agricultural, and small commercial and industrial scales (EERE n.d.b). DW is either installed on the &#;customer&#; side of the meter (e.g., a manufacturing facility meeting its own load) or to directly supply and support the distribution network. Residential turbines are 1&#;10 kW, whereas community-scale energy facilities have multi-MW turbines with total capacities up to 20 MW (EERE n.d.b). Like solar, the cost differences between distributed and utility-scale wind are large, especially for residential DW (6 times higher). However, by and , the LCOE for commercial, midsize, and large DW is projected to be about 1.6&#;1.8 times that of land-based utility-scale wind, which may make these types of DW projects comparable and even cheaper, when including the transmission costs associated with utility-scale projects . The cost gap for residential DW is also expected to narrow to 2.1&#;2.4 times that of utility-scale land-based wind. Another zero-emissions DER is small-scale or micro hydropower generation. Hydroelectricity is the second-largest renewable electricity source in the United States. Although utility-scale plants (capacity of more than 30 MW) typically employ dams, small run-of-the-river turbines (up to 5 MW) can serve as DERs. The micro plants have a capacity up to 100 kW and may be built where rivers, streams, and other moving water sources are available, generating enough power for a single home or community (EERE n.d.c). Compared to hydropower dams, smaller run-of-the-river units have reduced environmental impact, and projects may be approved faster. Small-scale hydropower is generally dispatchable but can be impacted by droughts.
Last, a hydrogen fuel cell extracts hydrogen through a low- or zero-emitting thermochemical process and produces DC power. Hydrogen is fed (either directly or by reforming hydrogen-rich fuels, such as methanol and ethanol) to the anode (negative electrode) and air to the cathode (positive electrode) in an electrolyte bath, which produces electricity (EERE, n.d.d). The by-products of this process are water, heat, and some CO2 (when pure hydrogen is not used). Fuel cells are quiet during operation and therefore good for distributed generation at or near residential and commercial places (FEMP ). Additionally, reversible fuel cells, under development, can store excess electricity generated by solar and wind in the form of hydrogen (EERE n.d.e). However, fuel cells are more costly than other distributed energy sources, and research is investigating what kinds of electrolytes could be used to make them more efficient. In addition, the process of creating hydrogen from fuels such as natural gas or propane would produce emissions, so their ability to deliver zero-emissions power is dependent on an abundance of renewables (Bartlett and Krupnick ).
Overall, the zero-emission DERs described may only partially displace the need for transmission expansion in a renewables-dependent grid. In particular, both distributed solar and wind power produce clean electricity close to end users and can reduce the need for lines. However, both are variable sources, so customers still need to be connected to the grid to maintain reliable supply. To the extent a region relies heavily on one distributed resource type , the grid may experience large surges in demand when that resource is unavailable, increasing transmission strain. Additional investments, such as demand management and on-site storage, can help address this problem. Ultimately, factors such as population density, geography, and resource availability will determine whether higher LCOE of DERs are offset by the siting, permitting, and buildout costs of new transmission needed for transporting power from centralized generation. More research that captures the full customer and system benefits of distributed generation, such as demand-side management, impacts on customer bills, benefits to disadvantaged communities, and resiliency with extreme weather events, is needed to determine how well DERs can reduce the need for new transmission.
Energy storage devices capture energy from the grid or other sources, such as renewable DERs, and make it available during times of unexpected high demand, weather-related outages, or lack of wind and sunlight. Lithium-ion batteries, such as those used to power cellphones, laptops, and electric vehicles (EVs), are most common. Other types of batteries are being developed that would increase efficiency, storage duration, and affordability. The systems exist at various scales&#;from large centralized systems to small home battery packs. Common residential storage involves battery-based inverters that can be used directly as backup power (e.g., a Tesla Powerwall that stores solar energy from rooftop panels) or an EV battery that can ship power back to the distribution grid and supply it to customers when needed. Distributed batteries could play an important role in supporting the reliability of distributed renewable energy and relieving strain on the transmission system.
Demand response involves consumers decreasing or shifting usage during peak periods in response to incentives provided by utilities, such as interruptible service agreements, time-of-use pricing, and critical peak pricing (OE n.d.). Initially, demand response options were largely limited to industrial customers who agreed to reduce electricity use when called upon, in exchange for compensation. More recently, it has become an option for residential and commercial customers as well, especially those using distributed generation resources, such as rooftop solar, EVs, and backup power. In the future, demand response could be used to shift electricity demand to low-cost hours to absorb renewable power that might otherwise be curtailed and use it to precool homes prior to peak heating hours or preheat water for later use (Wietelman et al. ). Distributed demand response is most effective when aggregated across customers. One house or business reducing its load may not do much for the grid, but when aggregated, demand response can shave a substantial portion off peak load, thereby serving as a virtual DER (Cummins Inc. ). The National Transmission Needs Study estimated that 5 percent of hours where energy is most expensive cover about 50 percent of the value of relieving transmission congestion (US DOE ). This concentration of value highlights a unique opportunity for technologies that can shift demand to relieve strain on transmission systems.
You will get efficient and thoughtful service from teao.
VPPs leverage a network of DERs and demand response systems to engage in active demand management. VPPs can include combinations of many kinds of physical assets&#;rooftop solar, DW energy, backup power generators, EVs, and batteries/inverters&#;that a utility or the system operator can control collectively to determine what resources to deliver to or take from the grid. VPP operators may also directly control customer devices, such as air conditioners, thermostats, and water heaters, remotely to help balance demand and supply on the system. In exchange, customers get lower electricity bills and/or financial incentives. However, establishing demand management programs and VPPs requires certain grid enhancements. Specifically, two-way communication technologies are needed to send and receive data and enable the remote control. Some examples include smart thermostats, advanced metering infrastructure (&#;smart meters&#;), and home-area-networks. Aggregation software is also crucial to bring together all individual sources effectively and create the coordination that enables a VPP. VPPs enable renewable integration and decarbonizing by supporting grid reliability and, as they are typically cheaper than building a new power plant, they also support affordability of electricity (Martin and Brehm ).
A virtue of battery storage systems, demand response, and VPPs is that they offer a greater degree of control to help balance the system that is not available from most individual DGs in isolation. To the extent that these systems can modify power draws from the grid to accommodate fluctuations in renewable supply, they can lessen the need to rely on large transmission interchanges between regions for that type of support. They could also reduce renewables curtailment more readily by absorbing excess generation to charge batteries or precool buildings during hours when power is abundant and cheap. For example, customers with storage systems and the right types of energy rate designs can use and discharge their batteries during hours with high net peak loads (and associated high prices) and charge them during other times when prices are low. VPPs are a relatively new grid solution, and it remains to be seen how effective they will be at smoothing consumption and relieving strain on generation and transmission systems.
Overall, the benefits of DERs over building transmission to utility-scale centralized generation include faster installation time and avoided energy losses and transmission costs, which may lead to lower-cost energy supply. Because DERs are smaller and often built on an existing site (e.g., rooftop solar on houses), the deployment is much quicker, and they face lower regulatory hurdles for siting and interconnecting with the grid than new transmission and utility-scale projects. Unlike with GETs, those investing in renewable DERs (such as residential and commercial customers who can transact with the distribution utility) are the direct beneficiaries of the investment, due to the energy that they provide the owner.
Despite their reliability and other benefits, DERs have limitations and face important barriers. First, establishing a system of DERs still takes space and might be unpleasant to those living nearby because of the noise and unappealing visual aesthetics of some types of resources, such as DW (EPA n.d.). Careful planning and consultation with affected parties is important to siting and implementing larger community-scale projects, and greater reliance on quiet resources, such as batteries, could offset some concerns.
Second, technical challenges can be associated with adopting and connecting DERs to the grid. These barriers primarily relate to the local utility&#;s ability to do so safely and within regulatory boundaries. Specifically, utilities must ensure that the DER does not negatively impact grid reliability, stability, and safety (Kim and Fischer ). For example, the increased variability in electricity production from DERs could threaten grid stability. Furthermore, the lack of visibility of the growing number of behind-the-meter DERs challenges local and regional grid operators&#; ability to do system planning and regulate power supply (Kim and Fischer ). The local distribution utility must be able to supply power to these households and businesses, including when outages or natural disasters occur, so the electricity demand of DER owners still needs to be taken into account in utility planning. Digital equipment interconnecting DERs to the grid and providing information to grid operators can help address the DER visibility challenge (Kim and Fischer ). Smart devices, such as smart meters, smart thermostats, electric heat pumps, and advanced inverters that adjust solar power generation allow DER owners to keep track of their resources in real time and utilities to monitor and control DER operations more efficiently. This digitalization can then be scaled up to aggregate DERs and serve as reliable VPPs.
Third, the increased reliance on electronic monitoring and digital communications raises important cybersecurity and data privacy concerns and challenges. The digitization and automated communication between DER owners and utilities or grid operators often uses the Internet, which is prone to hacking, ransomware, and other malicious attempts to destabilize the grid (Office of Cybersecurity, Energy Security, and Emergency Response and EERE ). This threat is enhanced when DER aggregators establish VPPs. Collectively, DER providers, equipment vendors, integrators, and operators need to work with the federal and state utility regulators and relevant government agencies to standardize robust procedures in cases of threats and attacks, prerequisites for DER approval, and technologies to ensure cybersecure systems and controls. Some best practices, including encryption, multifactor authentication, and skilled software security teams, need to be adapted to the specific DER deployment.
To get the best experience with www.aeso.ca, we suggest using a newer version of Internet Explorer/Edge, or using another supported browser such as Google Chrome.
ETS users may continue to log in using Internet Explorer 9 using the upper right hand link marked ETS Login.
If you want to learn more, please visit our website Household Device Damping wholesale services.