Reaching 100% renewable energy generation may seem like an audacious goal, advisory company Clean Edge says, but it is already happening. Hydropower has an important role to play, and will be a significant portion of many 100% renewable energy portfolios for many years to come.

"The goal of powering one’s company, utility, city, state, or nation with 50%, 75%, or even 100% renewable electricity would have seemed preposterous not long ago. But increasingly, a growing number of companies and governments are aiming to achieve such targets. And nobody is laughing," technology advisory company Clean Edge says.

Reaching the highest achievable penetration of renewables requires an all-of-the-above clean-energy approach, the company adds, and both existing large-scale and new small-scale hydro have a role to play.

In an executive briefing published in November 2015, Clean Edge says that although reaching 100% renewables may seem like an audacious goal, it is already happening. For example the country of Costa Rica recently achieved a national first – receiving all electricity from renewables generation during the first 100 days of 2015. This was primarily from a mix of hydro, which typically supplies about 68% of Costa Rica’s electricity but received a huge boost from heavy rains early in the year, along with about 15% of geothermal.

Furthermore, Kodiak Island in Alaska also managed to reach 100% in 2015. It used 30MW of hydropower, backed by 9MW of wind and 3MW of battery storage, to supply power for its 15,000 inhabitants. Aspen in the US state of Colorado also scored top marks in 2015 for its population of 6700. This was achieved by 50% hydro, along with wind, solar and geothermal.

In 2014 the El Hierro government in the Spanish Canary Islands (population of 550,000) joined the ranks of the 100% club. Its 11.5MW wind farm was backed by pumped storage. While the Austrian state of Carinthia achieved the goal in 2013 for almost 11,000 inhabitants primarily though hydropower and pumped storage, along with some solar and wind installations. Most impressively Iceland achieved the 100% target way back in 1982. Its population of more than 317,000 is served mainly by hydropower, supplemented with geothermal sources.

"The growth of renewable energy since the start of the 21st century shows why reaching high penetrations of renewable electricity is no longer a pipe dream for many corporations and governments," Clean Edge states.

As some of the examples above have shown, reaching 100% renewables is described as being currently very hard without large scale hydropower. According to the company briefing: "Although the much more mature hydro industry is not growing like wind and solar, long established hydro projects in places like Belize, Costa Rica and Scotland are making significant contributions to those nations’ ambitious renewable energy goals. With the added advantage of providing baseload, dispatchable power – and still providing the world’s leading source of energy storage – hydro will be a significant portion of many 100% RE portfolios for many years to come."
Furthermore a growing number of businesses are also choosing access to hydropower resources to locate energy-intensive facilities, such as Google’s data centre in The Dalles, Oregon in the US.

Future commitments

For many entities the 100% renewable energy goal is a long-term one but there is an increase in commitments to such a future. For example Costa Rica is aiming to achieve 100% by 2021 from expanding hydro and geothermal resources, as well as looking into storage. While Munich in Germany is striving towards it in 2015. Currently utilising 13 hydropower plants, the government is planning expansion of both hydro and wind power.

"As that momentum grows, it will build an increasing body of resources, best practices, and shared knowledge of the advancements and pitfalls on the road to 100% renewables," Clean Edge concludes. "In many ways, we are just at the very beginning of this game-changing new phase of the clean energy revolution: the shift to 100% renewables. It will be a marathon, not a sprint, for sure, but the pace shows no signs of slowing down."

Reference: Getting to 100. A status report on rising commitments among corporation and governments to reach 100% renewables. November 2015. A Clean Edge Executive Briefing.

Renewable micro grids

The oil dependency of some remote islands and communities around the world exposes them to several risks and drawbacks. Analysis by The Rocky Mountain Institute and Carbon War Room has shown that such communities can now have access to affordable renewable energy in the form of micro grids.

Various islands and remote communities have been actively embracing the transition from oil dependency to renewable generation. Lessons they have learned along the way include that:

  • Such a transition can reduce costs. In all cases studies increased reliance on more diverse and renewable powered micro grids led to reduced diesel usage.
  • Adding renewables enhanced system resiliency and stability.
  • Diverse resource mixes are less prone to failure than those depending on just one source.
  • Energy efficiency and storage are also important considerations. Indeed every community profiled in the report has already integrated or is currently considering the installation of flywheels, batteries or pumped storage energy systems.

Kodiak Island in Alaskan is the second largest island in the US and has been utilising hydro resources since 1984. In a drive to achieve 95% renewable electricity by 2020, the Kodiak Electric Association added multiple wind farms and a third hydro turbine. This has succeeded in reducing customer rates by 3.6% since 2000, and now means that residents can cost-effectively switch from oil as a heating fuel to electric heat pumps.

Combining wind with pumped storage at El Hierro in the Spanish Canary Islands has enabled high energy demand be met there: demand is unlikely to reduce as the island’s energy intensive desalination plant is required due to heavy dependence on agricultural production in a dry climate.

An extinct volcano crater where water can be pumped up to 700m provided an ideal location for the pumped storage project and facilitates the relationship between wind power and hydro. The size of this whole system has been determined based on projected electricity demand up to 2030 to ensure that the system can continue to provide renewable energy in the future.

In addition the Isle of Eigg in Scotland is utilising a mix of wind, solar and hydro to replace the community’s non-interconnected electricity system driven by diesel. Now renewables generate 87% of average annual generation.

Reference: Renewable Microgrids: Profiles From Islands And Remote Communities Across The Globe By The Rocky Mountain Institute and Carbon War Room. Published November 2015. Download at: