Mark Anderson had a lengthy resume as a successful project manager at the terminus of the Alaska Pipeline.

When he eventually relocated to California, he hired on with a major electrical contractor. Supervising the removal of hazardous materials, he accomplished in four months a clean-up job the company had struggled for years to complete.

His reward?

Anderson was fired, replaced by a subordinate earning half his salary.

After the initial shock, Anderson pulled up his entrepreneurial bootstraps and did what any savvy, young entrepreneur would do. He opened his own business – Geographica, an eclectic collection of international treasures – last December in a back alley two miles from the state Capitol.

“You get to be your own boss,” Anderson, who turns 60 in August, says with a smile. “I really enjoy the people who come through here.”

He is not alone. Older adults facing age discrimination or squeezed out by employers looking to cut costs are finding entrepreneurship a surprisingly realistic option in a rugged new economy.

For more than a decade, Pat Guerra has collaborated with the Global Social Benefit Incubator at Santa Clara University, helping hundreds of entrepreneurs start businesses targeting clean water, off-the-grid energy solutions, subsistence farming and similar ventures.

In January with a university colleague, Guerra launched the Encore Venture Accelerator Program, customized for older entrepreneurs.

“The program is specifically tailored to the needs of people over 50 in launching a venture,” he says of his first class of 10 students. “It greatly increases the probability of success.”

A whopping 25 million Americans between 44-70 hope to start their own businesses in the coming 5-10 years, according to a 2011 MetLife Foundation study. Half want to start what they consider a socially responsible enterprise.

Paul Tasner has already done just that. Tasner was a senior executive for Method cleaning supplies when he was downsized after the 2008 economic slump.

Two years ago at age 66, Tasner joined forces with his business partner – a recently laid-off architect – to start San Rafael-based PulpWorks, which designs and manufactures sustainable packaging for consumer products.

The two received intensive assistance from neighboring Venture Greenhouse, an incubator for green businesses. Venture Greenhouse helped them set priorities, create a business model, and find customers.

“We got so much great advice,” says Tasner. “And they really held our feet to the fire.”

Nancy Burkart worked at her family arts and crafts business for decades despite her frustration at its lack of toxin-free supplies. After a divorce, Burkart started Earth Safe Finishes online with her daughter in 2007.

“There’s no retirement now,” says Burkart. “You do what you need to do.”

Yet while pursuing lifelong dreams and serving a larger purpose are great motivators, they don’t always pay the bills.

“It’s all about financial literacy and risk management,” says Elizabeth Isele, co-founder of Senior Entrepreneurship Works, a Washington, DC-based non-profit started last year and has assisted 400 adults age 50 and over.

Isele says these entrepreneurs are part of an important economic shift in the United States. The title of her October Washington summit in the nation’s capital says it all: “New Engines for a New Economy.” (A Bay Area summit at Google headquarters in Mountain View is scheduled for July.)

In San Francisco, Encore.org (formerly Civic Ventures) helps job-seekers find encore careers and also encourages “encore entrepreneurs.”

Jim Emerman, Encore.org’s executive vice president, says along with green businesses, older entrepreneurs often target two areas: youth development and health improvement.

One San Francisco clinical therapist recognized how few children inside the foster care system received proper mental health care. Launched in 1994 as the Children’s Psychotherapy Project, the initiative pairs volunteer therapists one-on-one with foster youth. Now called A Home Within, the non-profit has 50 chapters in 22 states, winning Encore.org’s 2008 Purpose Prize for social entrepreneurship.

Isele says her organization targets unlikely entrepreneurs: low-income seniors.

“Sometimes they are greater risk-takers than the higher income makers because they know what’s at risk,” she says. “They’re investing in an idea, and they know they have to believe in it. And they are incredibly responsible.”

Isele ponts to Ireland – with its mandatory retirement age and stressed pension funds – as a model for older adults with its Senior Enterprise initiative.

“It is the program that is held up as the model program by the EU,” she says. “The EU commission is very interested in senior entrepreneurship.”

The key to success, says Emerman, is experience.

Older adult entrepreneurs target “all kinds of special needs that lend themselves to the kind of advice that someone with a lifetime of experience can bring to bear,” he says.

Lenders should take into account this very real “social capital,” says Isele.

“That should be considered equally with a credit report.”

Matt Perry wrote this article as part of the MetLife Foundation Journalists in Aging Fellows program, a collaboration of New America Media and the Gerontological Society of America.