Spring  >>  2010  

Renewable Energy Potential

GIS and Remote Sensing Roles

Modern civilization is extremely energy dependent, power consumption continues to grow and the average citizen doesn’t pause to think about the energy used by making a cell phone call, frothing a cappuccino, turning up the thermostat or surfing the internet. This lifestyle has been made possible by affordable energy relative to our overall cost of living. Today our individual energy costs are small but growing rapidly. Low-cost energy is completely dependent on non-renewable energy sources such as coal, nuclear power and petroleum. The increasing cost of energy has put a spotlight on the question of our future ability to support growing energy demands and has given researchers a chance to have a greater impact on the future, thanks to the current popularity of ‘green’ or renewable energy (RE).

By Natalie Cutsforth
Denver, Colo.

The future of RE is dependent on consumer willingness to change, corporate adaptation, and the cost/benefit analysis. Currently consumers don’t have a lot of choice when it comes to their household energy sources; they have one energy provider option and rely on that utility company to make all the fuel decisions. But that paradigm is changing. Electricity providers have increasingly diversified their fuel sources as technology and the cost of non-renewable fuels increase.

Investment in RE

Companies like Nexgen Energy Partners (Boulder, Colo.) have emerged to provide capital funding for site-specific RE installations, making it an affordable option to business, government and individuals. The financing of RE installations, a relatively new alternative for this market, is based on forecasted future increases of energy cost. Companies providing capital for RE receive applications from those looking for financing and use analysis tools that include remotely sensed data to determine whether the site is a fit for RE technology, using figures for wind and solar patterns as well as right-of-way, zoning, line-of-sight and factors that are less measurable, such as community resistance to the visual impact of wind and solar installations. Remote sensing, geospatial and engineering companies such as Woolpert (Dayton, Ohio) and Digital Globe (Longmont, Colo.) provide right-of-way data (Figure 1) and line-of-sight analysis (see Figure 2) used by RE financers in the decision making process.

Ted Rose of Nexgen explains, “We use remotely sensed data predominately at the outset of a project when assessing whether the site is suitable for renewable energy and what the best renewable energy blend is for the local wind and solar resource with respect to energy demand. The initial assessment using GIS (geographic information systems) analysis helps us quickly know whether we have a site that works.” Nexgen looks for development patterns, local zoning requirements, nearby residential development, wind, solar and small hydro sources.

Their specific matrix for determining cost/benefit are proprietary, but as a rule they want to make the end product for the customer work, keeping in mind that clients don’t want to pay a lot more for RE even if they can foresee future traditional energy costs rising. Following acceptance of a project, they suggest the solution, often a combined wind and solar one. A predominate concern is with the wind turbine height based on zoning restrictions. Nexgen has researched community attitudes to RE and is working on a white paper to help educate the public and reduce resistance to technology adaptation.

Data Availability

While financing has opened the door to smaller scale installation of RE and has empowered consumers to elect their own energy sources, the availability of data that supports the cost/benefit analysis and technology efficiency is the bottom line for energy companies and financiers; as a result the availability of data drives the consumer availability of green energy options. The scientific voices behind data and technology research are organizations such as National Renewable Energy Lab (NREL), a federal agency with large facilities in Golden, Colorado, and Electric Power Research Institute (EPRI), based in Palo Alto, California.

Two primary areas of focus for the application of remote sensing data and activities of NREL’s GIS service center are:

  • Assessing resources to understand distribution of natural RE supply, site suitability analysis and development potential for specific technologies. This process includes translation of data to assess competitiveness of RE with conventional technologies.
  • Providing services to those who rely on NREL in the form of application development and data. Some of this is for the general public and some is for other energy analysts at government agencies in the U.S. and internationally.

“The data component is substantial and often underestimated by our clients who come in for training. Generating the final map is easy; it’s insuring the accuracy and consistency of the data used for a study that is the largest effort,” according to Donna Heimiller, NREL GIS service center manager. NREL relies heavily on USGS (United States Geological Survey) data, specifically land use and elevation data and data that are satellite-measured, such as solar radiation and cloud data.

Wind data are numerically modeled, but the remote sensing sources used in analysis are predominately elevation and land cover, as they impact the wind speed closer to the ground.

Currently, wind source is the fastest growing RE technology, as it is the most cost effective and easy to implement for site specific installation, as well as for larger scale uses such as blending the wind power with coal and nuclear transmissions that predominate the energy market (see Figure 3).

T and D Challenges

Transmission and distribution are two of the biggest limitations to growth of RE. Many RE sources such as wind and geothermal are not near high population areas in the United States. Existing transmission infrastructure is harder to access for these resources, and storage of the energy is a constraint. NREL’s GIS team looks at transmission lines relative to RE resources for use in analyzing cost.

The data sources available for capacity on transmission lines is limited and patchy on a national scale, so the team often makes assumptions about the capacity based on length of the line, starting with a baseline of national transmission line datasets purchased from commercial companies such as Platts (New York, N.Y.). Pockets of detailed information on transmission capacity exist but they are not easily digestible for use in analysis. No flow exists nationally nor is there consistency in the data before NREL begins to work with them. Therefore they leverage planning data and analyze proximity to main transmission.


NREL has created an online tool, In My Back Yard (IMBY, www.nrel.gov/eis/imby), that uses satellite imagery streamed from Google Maps (Mountain View, Calif.) as the background data. The tool is used for making rough decisions on solar photovoltaic (PV) and wind specific to distributed scale RE. IMBY gives users information on potential generation of specific RE resources. It presents results so the end user can make an informed choice but doesn’t make the assessment decision.

NREL predominantly serves citizens by providing research data to state energy offices and vested interests inside states. For example, they are working with a group of seven states to understand opportunities for solar PV regionally, providing training with IMBY and other assessment tools. The focus of their research is on technical feasibility and cost, not on consumer attitudes or acceptance of RE. See Figure 4 for NREL map of solar potential in the U.S.

Ultimately NREL develops web-based and analytical models that can be used by the state, or in some cases a city, to determine the best technology blend to expand RE for the area. Other types of field activities involve making a deeper analysis in a specific region. Currently there is an integrated deployment group that is working with Hawaii; the island state imports 85% of their energy. The NREL team, in conjunction with local government participants, looks at all the potential options, impacts and optimum mix for RE. This deeper analytical work has helped find additional areas where it makes economic sense to use RE.

Outside of government collaboration, NREL staff member Chris Helm has led a community project to collect data from the general public and installers on cost and location of existing solar PV installations. NREL is trying to incentivize developers to put their data up and allow NREL to highlight their work. There is a lot of solar PV and local wind turbine installation data activity that NREL doesn’t have access to because it’s privately implemented, making studies of adaption of RE harder to quantify.

EPRI's Role

While NREL collects, compiles in a meaningful form and analyzes the data, organizations such as EPRI use that data to drive technology development decisions. For example, NREL is partnering with EPRI on offshore wave generation energy studies. NREL is modeling the data and creating regional models while EPRI tests and develops the equipment. NREL integrates the wave data collected with other databases, specifically offshore wind data that take into consideration wind, wave and water depth to determine turbine anchor efficiency.

EPRI’s mission is to keep electricity affordable and environmentally sustainable, focused on generation, delivery and environmental impact. As a public-private, non-profit organization funded by a blend of utilities and government, EPRI acts as a resource for regional stakeholders on electric energy findings that can help inform policy makers and utility company decisions. Each energy source is seen as valuable, especially because RE availability is different in different parts of the country and world. With a full portfolio of energy options, consumers are going to be better off in terms of cost-effective, sustainable solutions; wind, solar PV, hydro, coal and nuclear are all necessary.

RE must move to meet the need of the grid to be more predictable and less variable while becoming cost competitive. EPRI looks at pairing RE with other technologies to predict when utility providers can rely on them, recommending Smart Grid technologies to ensure that electricity distribution is consistent. Smart Grid enables two-way flow of information and electricity that can be controlled and monitored to keep the electricity flowing where and when it’s needed. It requires high-powered computing and accurate data. Ellen Petrill, Director of Public/Private Partnerships of EPRI explains, “Pieces of Smart Grid technology are being implemented regionally and within specific utilities. Right now electric generation companies supply electricity into the grid. It flows to the path of least resistance and we don’t control it that well because we haven’t had cost-effective control devices.” Devices exist now to sense and provide control, but they are very expensive to implement broadly given the size of the U.S. electric system. EPRI helps utilities and government determine the most cost-effective approach to implement Smart Grid by providing research data to assist in the decision making.

In the evolution of RE technology at the utility company implementation level, it is still more expensive and smaller in scale. Base load power is important to maintaining consistency in meeting consumer electricity demand, and EPRI concedes that giant coal and nuclear plants are very valuable to keep the system going. The average wind turbine produces about 2 megawatts, so wind farms are still small producers compared to a 1000 or 1500 megawatt nuclear plant.

The scale and cost of transmission, base load power and storage are some of the most significant barriers to RE growth. “Eventually we have to stop burning things, and combustion is a large part of our electric systems, although we are going to get smarter about burning things and keeping emissions from going into the atmosphere. Maybe in 100 years every rooftop will be a solar structure integrated into the system,” speculates Ellen Petrill.

EPRI doesn’t have a GIS team that services the organization, relying instead on spatial data from NREL and contractors for input into their modeling of technology cost/benefit analysis. The company focuses on the technology, and then gives the tools to utility companies to use. Those tools are predominantly reports, findings of research projects (see Figure 5), and occasionally software tools. Sometimes they commercialize and test or license technologies, or identify methods and best practices for applying technology. In the research process, EPRI looks at what resource is available and where it would be most effective to harness. Ellen Petrill suggests, “That’s why geothermal is another exciting possibility. If technology advancement allows for access, it’s a consistent, sustainable source of power. It’s almost like free energy.” Reducing exploration costs with GIS tools will be very helpful.

Consumer use of RE relies heavily on cost/benefit. Research, technology development and increasingly more accurate data are driving the future of renewable energy growth by identifying greater efficiencies and by educating decision makers. In parallel, the increasing cost of traditional energy sources will continue to drive the demand for research into sustainable and renewable sources of power. For the moment, development is not moving at the same speed as growth in consumption. Technologies such as wind and solar PV are critical bridges to the next big discovery of a fuel source that will sustain our energy demands.

Ted Rose of Nexgen Energy asserts, “We don’t have enough time to make the changes in clean energy technology that the market demands. This is a step in the necessary direction.” To avoid forced major lifestyle changes, research by organizations such as NREL and EPRI is essential to “keep electricity affordable and environmentally sustainable. It’s going to take a lot of innovation to make that happen,” says Ellen Petrill.

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