Planning the urban climate of the future

What a tree needs to grow and how it affects its surroundings vary from species to species. This makes it increasingly important for cities to adapt the urban tree cover to local conditions.

A team at the Technical University of Munich (TUM) has developed the online tool CityTree. Cities, municipalities and interested individuals can use it to find out how 12 common tree species are growing in 34 German cities and how they will benefit the local climate in the future.

Trees reduce heat stress on hot days, emit oxygen into their surroundings and bind climate-damaging CO2. This adds up to a decisive contribution towards maintaining the best possible quality of life in cities as the world heats up. A team working with the forest scientist Prof. Thomas Rötzer has investigated the advantages of selected tree species for the urban climate and the conditions under which they thrive.

To conduct the study, the researchers measured more than 5,000 urban trees throughout Germany, took samples from them and analyzed their surroundings. The focus was on lime trees, locust trees, plane trees and nine other species that make up 60% of the urban tree cover in Germany.

The data were then used to create an interactive model called CityTree. Access to the tool is free of charge. It is mainly intended for cities and municipalities, but can also be used by ambitious hobby gardeners when planning tree plantings in their own gardens.

Creating virtual trees

Users can define a virtual tree with just a few clicks. After choosing from among 34 cities and 12 tree species and defining such characteristics as soil type, the level of soil sealing and light exposure, the user sees how much CO2 the tree will bind, how much it will cool its surroundings and the quantity of water it will use.

The preview can also reflect various climate scenarios. The period from 1991 to 2000 simulates tree performance in the current climate, while 2003 represents a dry year. For the period from 2081 to 2090, the user can choose between climate scenarios based on 1°C or 4.8°C of global heating.

The data illustrate the importance of detailed planning for urban greenery. Cities like Berlin and Würzburg, with low precipitation and high temperatures, benefit more from plane trees and other drought-tolerant species. A city like Munich, with relatively high rainfall, can plan for species such as small-leaved lime and horse chestnut trees if the tree pit is large enough.

Planning for 2081 starts now

Although 2081 might seem like a long way off, "It is urgent for cities to take action now and critically assess their tree cover. Planting decisions shouldn't be based solely on aesthetics," says Thomas Rötzer.

"A tree has to grow for many years before it has a noticeable impact on urban climate. In the past, cities and municipalities lacked concrete information for planning optimized tree plantings and to assess the performance of existing trees. Through the app, we have converted scientific data into a usable format with practical benefits that can address this urban planning shortfall."

The research team recommends that local authorities develop a systematic overview of their trees. So far, there are only a few resources that would represent an "urban tree cadastre." With this knowledge, cities could establish programs with concrete targets and measures for optimal adaptation to the challenges of climate change.

The research team is currently working toward that objective. Using satellite images, they are surveying the tree population of Munich and assessing its potential growth and the benefits to the urban climate. These data can then be used for the sustainable management of the city's tree cover.

Source: Phys Org

Reinventing the Waterwheel

In the foothills of the Himalayas, a group of villagers hauled a sturdy metal waterwheel into place. Its horizontal blades soon caught the rushing water of the stream directly below it. The machine began to spin, and electricity began to flow.

A waterwheel installed in rural Nepal. Photograph: Michael Erhart

The roughly 2-metre-tall waterwheel, installed in a village in Kashmir, India, was the result of years of design work and development by researchers at the Technical University of Munich (TUM) and partners.

“You have this continuous power flow,” said Michael Erhart, the chair of renewable and sustainable energy systems at TUM. “It’s not intermittent like the radiation of the sun or wind power.”

Waterwheels have been around for thousands of years. Formerly used to drive mechanical processes such as milling or hammering, they were a crucial component in the industrial revolution. Today, waterwheels connected to generators can produce zero-carbon electricity as they spin.

An Archimedes screw-style waterwheel was installed along the River Wandle in London in 2012. The 8.5kW system generates enough electricity to power 18 homes.

Some experts argue that greater adoption of electricity-generating waterwheels could help to decarbonise energy systems. For the Kashmiri villagers, their new waterwheel offered energy independence. It was installed alongside other renewable energy resources, including a microgrid, between 2022 and 2024.

Erhart’s colleagues had previously supported the deployment of a similar waterwheel in Nepal, as well as a demonstration prototype in Tegernsee, southern Germany.

The waterwheel in Tegernsee. Photograph: Michael Erhart

Before the new waterwheel arrived, the community in Kashmir had to rely on a centralised electricity grid that often let them down. “They had power cuts of weeks or even months,” said Erhart. The renewable energy kit meant the village could now survive off-grid.

The climate crisis and bouts of extreme weather are putting additional strain on power grids in India and Nepal. Decentralised microgrids connected to a mix of renewables including solar and waterwheel devices could, in theory, help remote communities to become energy self-sufficient.

The generating capacity of such wheels ranges from about 300W to 1kW, according to Erhart, depending on the flow of water. During flooding, it is possible to set up the wheel so that torrents of water can bypass it, meaning electricity generation may continue uninterrupted.

Erhart’s instructions for building the waterwheel are freely available online. The cost of assembling one could come to as little as $1,000 (£819), he estimated.

Separately, another kind of electricity-generating waterwheel was set up in Northern Ireland recently. The historic waterwheel attached to an old mill in Co Fermanagh was fully restored and now provides electricity to a restaurant within the building.

The Tully Mill restaurant’s waterwheel outputs roughly 1.5kW, according to Patrick Drumm, group treasurer of the Killesher Community Development Association. The wheel powers about 10 strong outdoor lights at the restaurant, though Drumm added that the cost of installing the system was significant at about £49,000. The project was made possible thanks to funding from the National Lottery.

It would be advantageous to use waterwheels even more widely, said Gerald Müller at the University of Southampton. Müller said a handful of companies in Germany currently restore or build waterwheels for electricity generation. “I was talking to the owner of one [of those companies] the other day and he was saying his books are pretty much full for the next three years – interest has increased because of the rise in electricity prices,” he added.

Müller’s research indicates that the efficiency of waterwheels, in terms of converting water power into electricity, can be as high as about 85%, .

One possible downside of waterwheels is the risk they might pose to aquatic life. However, research indicates they have a minimal impact on fish, for example.

Müller said that besides supplying private homes and buildings such as restaurants or hotels, waterwheels could also power pumps designed to move water up hills and irrigate fields on mountainsides.

Source: The Guardian

Human Settlements dep’t issues challenge to build resilient communities

The Human Settlements department has invited the private sector to collaborate with the government in building communities that are resilient in the face of climate change and natural disasters.

Undersecretary Henry L. Yap of the Department of Human Settlements and Urban Development (DHSUD), in a keynote speech at a forum organized by BusinessWorld, said “all stakeholders” need to work to create resilient communities.

“To achieve our goal, we need a united front. The realization of an inclusive, resilient, and sustainable human settlements entails coordination and support from all stakeholders, as well as significant funding and investment,” Mr. Yap said at the BusinessWorld Insights Forum, “Building Sustainable and Inclusive Communities for the Future” in Makati City.

“We are inviting the private sector partners, business people and leaders, development partners, and our local government units to partner with us in building a better Philippines,” he added.

Urban planner and Palafox Architecture Group, Inc. President Felino A. Palafox, Jr. said the Philippines needs to have 100 new “sustainable, resilient, and smarter” cities by 2050 to house a population projected to grow to over 150 million.

“By 2050, it is forecast that the Philippines will be the 16th largest economy in the world. There will be 150 million Filipinos by 2050, of which 70% will be urban population. We need 100 new cities by 2050. Otherwise, our existing cities will be as bad, if not worse, than Metro Manila today,” he said.

“We need strong political will with visionary leadership, urban design, and excellent management,” he added.

Ramon Rivero, Robinsons Land Corp. head of corporate planning, strategy, and sustainability, said that sustainable real estate development is an imperative rather than an option.

“Our cities are expanding at a fast rate and with this growth comes the need for more housing, commercial space, and infrastructure. However, this growth must not come at the expense of our environment,” Mr. Rivero said.

“We have to make sustainability very easy for our people, be it in the form of incentives or form of education. It has to be an easy option. You have to design it in a way that is easy and accessible for them to implement,” he added.

TruNorth Homes Founder and Chief Executive Officer Earl Forlales said that sustainable infrastructure and solutions should be more accessible to promote broader adoption by consumers.

“There is no use for a well-planned sustainable community if people cannot afford to live in it. If we’re able to infuse sustainable features and still make it affordable, that would make a sustainable community,” he said.

“Sustainable infrastructure has to be affordable to the regular consumer. The more that we can make sustainable solutions more affordable, behavioral change will naturally follow on the consumer level without forcing it,” he added.

Yvonne Flores, Gokongwei Group head of sustainability and corporate social responsibility, said inclusive urban planning should be approached systemically.

“It is looking at the overall system and implementing solutions systemically,” she said.

“Resilience is an existential must for all of us. We must make sure that the vulnerable within our communities are included in the solutions we’re looking at. It’s about looking those who are vulnerable and ensuring that because we are part of the community, even the vulnerable are protected and included in the solutions that we are looking at,” she added.

Aboitiz Infracapital Economic Estates Vice-President Jolan Formalejo said that committing to sustainable urban development should be the guiding principle in planning inclusive communities.

“With this comes making sure that inclusivity is integrated. The solution is to decongest these cities by providing new regional areas,” he said.

“Once we start in the regions, we have the full opportunity to make a difference,” he added.

BusinessWorld Executive-Vice President Lucien C. Dy Tioco said sustainable cities and communities remain a challenge for the Philippines.

“In an era marked by rapid urbanization and unprecedented global challenges, the need to make our cities and communities inclusive, sustainable, and resilient has never been more critical,” he said.

“Even the effects of recent Typhoon Carina and the southwest monsoon in Metro Manila and Luzon alarm us once again of how crucial it is to make our communities not just ready for disasters but capable of mitigating their impacts to avoid casualties,” he added.

Source: Business World