Here are some fascinating figures (from Environment America) about the growth of renewables in the United States:

• Between 2011 and 2020, renewable energy production (solar, wind, and geothermal) grew at an average rate of 15% per year. Assuming this same rate of growth, the US could be on target to meet all of its electricity needs with renewables by 2035.

• The US produces 23x more solar power and 3x more wind power than it did in 2011.

• The median efficiency for new residential solar panels increased by 37% from 2010 to 2019. At the same time, the cost of distributed solar photovoltaic systems fell by 71% and the cost of utility-scale systems fell by about 80% between 2010 and 2018.

• During this same time period (2010-2018), the cost of land-based wind power fell by 66%.

• The median range of new electric vehicles increased by more than 3x between 2011 and 2020. The median range is now more than 250 miles on a single charge. By the middle of this year, cumulative plug-in EV sales surpassed 2 million units.

• Texas is the US state that currently produces the most renewable energy.

To download the full report by Environment America, click here.

Photo by Nuno Marques on Unsplash

Five cities. Five stories.

Here is a short film by Nils Clauss and Neil Dowling, which recently premiered at the Seoul Biennale of Architecture and Urbanism. (If you can't see the embedded video above, click here.) The film is named after this year's Seoul Biennale (which is going on right now until the end of October) and focuses on five crossroads of city life that were put forward by French architect Dominique Perrault: above/below, heritage/modern, craft/digital, natural/artificial, and safe/risk.

To illustrate these urban crossroads, the filmmakers visit New York, Seoul, Mumbai, Paris, and Nairobi. But instead of interviewing so-called "experts", these crossroads are examined from the perspective of people just living through them. The documentary is very well done. And having just come back from Paris, I can say that I think they chose the right city to tackle the heritage/modern crossroad.

To close things out, I would like to share one screenshot from the film. Here you can see an ingenious little urban table that slips over a street bollard. It's just perfect. There is so much that can be done to better activate our streets and public spaces.

Building height and density are not one and the same. You can have tall buildings configured in a low-density way (think post-war towers in the park). And you can have low/mid-rise buildings configured in a high-density way (think Paris and Barcelona). This is one of the reasons why it is important to decouple density and tallness when thinking about our cities.

This line of thinking is the approach that a recent study took when trying to determine the optimal built form for minimizing climate impact. In the study they define four building typologies: 1) high density, high-rise, 2) low density, high-rise, 3) high density, low-rise, and 4) low density, low-rise.

What they found was that taller environments tend to have higher life cycle GHG emissions, but that lower-density environments are (obviously) far more land consumptive. To determine life cycle GHG emissions they looked at both embodied and operating emissions, which is why the taller stuff didn't score as well under their methodology. There's typically a lot of concrete and steel in tall buildings.

This lead the team to conclude that if you want to optimize around climate impact, you should probably aim for that perfect middle ground: dense, but not super tall.

But as Joe Cortright (City Observatory) rightly pointed out in his email newsletter, one of the big limitations of this analysis is that it does not consider transportation-related impacts. And since we know that transportation is one of if not the largest source of GHG emissions and that how we get around is heavily dependent on land use patterns, it is probably an important piece to consider.

Photo by Alfons Taekema on Unsplash