Dive Brief:

• The Iowa Utilities Board (IUB) has approved MidAmerican Energy's 591 MW Wind XII project, which the utility hails as a major milestone in its work to provide customers with a cleaner energy mix. The utility says the new green resources will allow it to produce renewable energy equal to 100% of its customers' annual usage.
• But MidAmerican will still need its large coal fleet to meet customers' demand at times when the wind isn't blowing, and environmental advocates have called the company's 100% renewables claims "misleading."
• MidAmerican expects to complete Wind XII in late 2020 at a cost of about $922 million. Once completed, the utility will have more than 6.6 GW of renewables in Iowa.

Dive Insight:

There is no question that MidAmerican has done significant work to transform its generation fleet. Coal supplied 70% of its electricity as recently as 2004, but today makes up less than a third.

But just how close is the utility to 100% renewables? The debate highlights the difficulty in squeezing all carbon-emitting resources out of a portfolio, something even Google admitted to struggling with in a white paper released earlier this year.

"Wind XII will transform our 100 percent renewable energy vision from a bold dream into a reality," MidAmerican Energy President and CEO Adam Wright said in a statement earlier this year.

But the devil is in the details — or in this case, the very last line of the press release: "MidAmerican Energy will continue to use its natural gas, nuclear and coal-fueled plants to ensure reliable electric service even in times of low wind," the utility said.

The Sierra Club questioned MidAmerican's 100% renewable energy claims and the cost-effectiveness of the utility's coal fleet, which it says is still almost 3 GW.

"MidAmerican's assertion that it can generate a large amount of its electricity from coal while also claiming to meet 100% of its customers' needs with renewable energy is at best extremely misleading, and may seriously jeopardize Iowa's longterm ability to continue to market itself as a renewable energy leader," the group said in its October filing on the Wind XII proceeding.

In its statement following the IUB approval, the group says it supports development of renewable energy and "commends the approval of Wind XII."

But Sierra Club also used the proceeding as an opportunity to cast scrutiny on the company's coal resources and in its filing called for MidAmerican to submit a "comprehensive study of the cost-effectiveness of its existing generating assets, or an integrated resource plan," regardless of whether advanced ratemaking principles were approved for Wind XII.

"It's disingenuous for MidAmerican to claim that it will achieve its '100% renewable energy vision' with Wind XII, when the truth is that the company owns one of of the largest coal fleets in the country," Sierra Club Senior Campaign Representative Elizabeth Katt Reinders said in a statement.

According to the group, MidAmerican will continue to operate one of the 20 largest coal fleets in the country.

The utility said the project "will help us reach our 100 Percent Renewable Energy Vision to provide renewable wind energy to our customers," in a statement.

​Google has discussed similar issues: the company had purchased 2.6 GW of renewable capacity, which is more than sufficient to cover its demands for clean energy, but the resources are not fully aligned with when the electricity could be delivered.

The technology company reached its 100% renewable energy purchasing goal last year, but says it is now working on the "much more challenging" long-term goal of powering operations on a region-specific, 24/7 basis with clean, zero-carbon energy.