The best spots for solar and wind farms, with the least need for new poles and wires

Australia, like many parts of the world, is racing to add more solar and wind power to its grid. But as we push toward a cleaner, greener grid, a key question is: Where should we build all these solar and wind farms?

The answer isn’t simple. Many factors influence where solar and wind farms get built, from access to solar and wind resources to the geology and hydrology of the land and proximity to roads, skilled workers, and transmission lines. Throw in social, cultural, and environmental concerns, plus government incentives or disincentives, and there’s a lot to juggle. But there’s one factor getting increasing attention recently: access to existing transmission.

Building new transmission lines isn’t easy. They often have to cut across dozens, even hundreds, of properties and are hard to hide. Solar and wind farms, on the other hand, can often be tucked into just one or a few properties. So, getting access to those properties is much simpler.

But that’s not the only problem. Transmission lines usually face serious social push-back. Some people don’t want high-voltage lines running through their backyard despite large compensation payments of around $200,000 per km. Since building new transmission infrastructure is a challenge, making the most of existing infrastructure is key when siting new solar and wind farms.

The Renewable Energy Heatmaps developed by the RE100 team at the Australian National University, and published in a new paper, provide a visual representation of the most suitable places to build solar and wind farms based on the most critical siting factors: 

– Access to good solar and wind resources;

– Proximity to existing transmission and major cities;

– Exclusion of sensitive areas such as national parks, native forests, urban areas and steep slopes.

Other factors, such as access to roads or a skilled workforce, are less of a dealbreaker. They can usually be worked around, or their impact on siting decisions is slow to change over large areas. 

The heatmaps simplify this complex data into an indicative cost of electricity (in USD/MWh) for each 50 m x 50 m pixel. The maps are color-coded to show the areas with the lowest and highest costs (Class A to E), as well as areas that are completely unsuitable.

How to use the heatmaps

The heatmaps are available online through the ANU RE100 Map and they are interactive. Users can zoom into specific areas and get detailed information about each spot’s suitability for solar or wind development. 

Twelve scenarios are modelled for Australia (6 for solar; 6 for wind), including high, medium and low-cost assumptions and overhead or underground connection powerlines configurations.

For example, one map assumes an overhead 220 kV powerline connecting the hypothetical solar/wind farm at each pixel to load centres and the high-voltage network, while another assumes an underground powerline, which costs 10 times more but might be used if visual impact is a key concern.

Land tenure and land use data are also included, though they don’t affect the cost calculations directly. They’re just extra information that could help developers decide whether a site is right for them. For example, certain land uses or tenure types (like farming or grazing land) might be more suitable, but the final decision still rests with the developers.

Empowering landowners

One of the key motivations of this study was to empower landowners in the development of solar and wind farms. Traditionally, landowners didn’t have access to the key data that could help them evaluate their land’s potential for solar and wind development.

Developers, on the other hand, often have vast information at their disposal, and deep knowledge and expertise in locating prospective sites. There is substantial asymmetry in knowledge when developers enter negotiations with landholders, communities, and governments.

With the heatmaps (50×50-meter resolution), landholders can now see exactly how suitable their property is for solar or wind projects. This gives them the information they need to have more equitable, informed, and potentially more active discussions with developers.

With better transparency, groups of landowners can also work together to secure better terms and accelerate project approvals. Developers also benefit from faster, smoother negotiations with communities.

But it’s not just landowners who can benefit from these heatmaps. Local governments can use this tool to identify areas with strong potential for solar and wind development, attracting new projects and the economic activity they bring.

Meanwhile, state and regional governments, as well as transmission companies, can identify promising renewable energy zones where new or upgraded transmission infrastructure might be needed. This helps focus efforts on the most viable regions for solar and wind farms.

Dr Cheng Cheng is senior research officer, 100% Renewable Energy Group, School of Engineering, College of Systems & Society, The Australian National University. Andrew Blakers is a Professor of renewable energy engineering at the Australian National University.